One tool that has become increasingly important to web page authors is a multi-browser testing tool. The tool permits authors to view and test their web pages in multiple web browsers. As an example, if a uniform resource locator (URL) such as “www.abc.com” is provided to such a tool, a series of renderings of the content, as displayed in different web browsers (e.g., Internet Explorer®, FireFox®, Safari®, Chrome™ . . . ), is returned. These renderings, which are created by the actual web browser engines, can be compared side-by-side, overlaid, and interrogated to identify differences, which are typically due to the way each web browser implements HTML (HyperText Markup Language) and CSS (Cascading Style Sheets) markup. Once the differences are isolated, the web page author can make adjustments to minimize or eliminate the differences.